Microphone assembly



May 16, 1961 F. SWINEHART 2,984,713 MICROPHONE ASSEMBLY Filed Dec. 7,1959 hVE Hfmr Franz Snume/nzrf E J7EE.

United States Patent G NHCROPHONE ASSEMBLY Frank Swinehart, CedarRapids, Iowa, assignor to The Turner Company, Cedar Rapids, Iowa, acorporation of Iowa Filed Dec. 7, 1959, Ser. No. 857,685

8 Claims. (Cl. 179-167) The present invention is directed to an improvedmicrophone assembly and has particular utility where an intermittentlyoperated microphone is to be employed.

For some applications of sound systems, such as public address systemsand radio dispatching installations, it is frequently desirable toprovide both a manually operable energizing switch for the microphone,and an automatically operable switch for the same purpose. Themicrophone assembly of the present invention meets these needs byproviding energizing switches for the microphone which selectivelyconvert the microphone from the manually operable condition to anautomatic energizing condition.

In accordance with the present invention, the microphone assembly isprovided with a base which houses a multi-contact switch, such as aleaf-type switch for selectively energizing the microphone. A manuallyoperable switch operating lever cooperates with the switch to energizethe microphone whenever desired. A second switch, of thepressure-responsive type, is associated with the base to operate thesame switch solely by the weight of the assembly which it bears. Whenthis pressure-responsive switch is in the circuit, the microphone isenergized when the microphone assembly is lifted from a support so thatit is immediately energized when raised to the level of the mouth. Uponreplacement of the microphone assembly on the supporting surface, thepressureresponsive switch operates to deenergize the microphone andthereby eliminate the transmission of extraneous signals betweenintervals of use.

An object of the present invention is to provide an improved microphoneassembly having both manual and automatically operable energizing means.

A further object of the invention is to provide an improved pressureresponsive switch for selectively energizing a microphone.

Other objects and features of the present invention will become apparentto those skilled in the art from the following description of theattached sheet of drawings which illustrate a preferred embodimentthereof.

In the drawings:

Figure 1 is a side elevational view of the improved microphone assembly;

Figure 2 is a plan view of the microphone base, with the cover removedto expose the parts;

Figure 3 is a side elevational view of the structure shown in Figure 2,taken along the line III-III of Figure 2;

Figure 4 is a cross-sectional view taken substantially along the lineIV-IV of Figure 2; and

Figure 5 is a schematic diagram of the switching cir' cuits involved inthe microphone assembly.

As shown in the drawings:

In Figure 1, reference numeral indicates generally the improvedmicrophone assembly including a microphone 11 which may be anyconventional type microphone such as a crystal or dynamic microphone.The

ice

microphone housing also includes a neck portion 12 which terminates in abase housing 13.

Extending through the base housing is a manually operable switchoperating lever 14 and a locking means 16 for holding the switchoperating lever 14 in microphone-energizing condition.

The automatic energizing feature is provided by a pressure responsiveswitch 17 extending from the base of the microphone assembly and intocontact with a supporting surface 18. When the microphone assembly 10rests on the supporting surface 18, as illustrated in Figure 1, thepressure responsive switch 17 deenergizes the microphone assembly butthe microphone can be energized in that condition by depressing themanually operable switch operating lever 14.

Turning now to a consideration of the circuit diagram as shown in Figure5, the output of the microphone 11 has one portion grounded as indicatedat numeral 21 and the other lead 22 is arranged to be connected to anaudio amplifier or the like. Lead 22 is shielded against pickup by agrounded shield 23.

A manually operable switch consisting of a switch arm 24 and a contact26 serves to transmit the output of the microphone 11, when the switchis closed, to the audio amplifier.

In parallel with the manually operable switch are a pair of switchesarranged for automatic energization of the microphone assembly. Thepressure responsive switch 17 actuates a switch arm 27 against thecontact 28 to close this switch when the microphone assembly 10 islifted from its supporting surface. A disabling switch 29 is in seriesrelation to the pressure responsive switch so that the pressureresponsive switch may be removed from the circuit if the operation is tobe strictly manual.

The switching circuit shown in Figure 5 may also in clude switchingmeans for controlling energization of the audio amplifier, or othercircuits associated with the microphone. For this purpose, the switcharm 24- may be mechanically connected to a switch arm 31, the switch arm27 may be manually connected to a switch arm 32, and the disablingswitch 29 may be mechanically connected to a switch 33.

Figures 2, 3 and 4 of the drawings illustrate a mechanical structure forthe switching circuits shown in Figure 5. As seen in these figures, thebase 13 includes a removable base plate 34 upon which the variousswitching means are mounted. The switch operating lever 14 consists of aswitch bar 36 extending through the base housing, as shown in Figure l.The switch bar 36 has a pair of opposed arms 37 and 38 which arepivotally mounted in a pair of opposed ears 39 and 41 struck upwardlyfrom the base plate 34.

The switch itself may consist of a multi-contact leaf spring switchgenerally indicated at numeral 43 in the drawings. As best seen inFigure 4 of the drawings, the switch 43 may include leaf spring contactarms secured at one end by supporting blocks 44. The switch operatinglever 14 is arranged to bring the switch arm 24 into electrical contactwith the contact 26 and thereby close the circuit to the microphone.Another pair of switch arms are actuated by the pressure responsiveswitch 17. The latter may consist of a depending contact button 46supported from a resilient support plate 47 having opposed arms 48 and49 secured to the base plate 34 by means of rivets 51 and 52.

When the microphone assembly rests on a supporting surface 18 asillustrated in Figure 4, the operating button 46 is forced inwardly, bythe weight of the microphone assembly and breaks the electricalconnection between the switch arm 27 and the switch arm 28. The openingof this switch thereby deenergizes the pressure responsive switch butthe microphone can still be energized by depressing the switch operatinglever 14 to cause the contact arms 24 and 26 to engage. Release of thepressure on the switch operating lever 14 breaks the contact betweenswitch arms 24 and 26 by virtue of the nat ural resiliency of the leafspring arms.

Thus, the switch can be operated from either of its opposed surfaces,either by the switch operating lever 36, from the top, or by thepressure responsive switch 17 from the bottom. An insulator strip 53separates the two sections of the switch from electrical contact.

When it is desired to hold the microphone in energized condition, thelocking cam 16 is pivoted about a pin d carried by an car 57 struck fromthe base plate 34. The lower end of the camming lever 16 is received ina slot 38a appearing in the arm 38. When the lever 16 is moved to itsover-center position, the switch arm 24 and the arm 26 are in continuousengagement, and the microphone is continuously energized. While thewiring leads have been eliminated from the drawings in several of thefigures for purposes of clarity, it will be understood that themicrophone assembly also includes an output cable 61 for connecting themicrophone to the other circuits. It will also be appreciated that ifthe switches 31, 32 and 33 of Figure 5 are to be included in themicrophone assembly, the switch 43 may also include a parallel set ofcontact elements for that purpose as illustrated in Figure 2 of thedrawings.

It will be evident that various modifications can be made to thedescribed embodiment without departing from the scope of the presentinvention.

I claim as my invention:

1. A microphone assembly comprising a microphone, a base supporting saidmicrophone, a switch operating lever supported by said base, amulti-contact switch actuated by said switch operating lever to energizesaid microphone, and a pressure responsive switch on said base arrangedto energize said microphone when said assembly is raised from asupporting surface and arranged to deenergize said microphone when saidassembly is resting on said supporting surface.

2. A microphone assembly comprising a microphone, a base supporting saidmicrophone, a switch operating lever supported by said base, amulti-contact switch actuated by said switch operating lever to energizesaid microphone, releasable locking means for holding said lever inswitch closing relation, and a pressure responsive switch on said basearranged to energize said microphone when said assembly is raised from asupporting surface and arranged to deenergize said microphone when saidassembly is resting on said supporting surface.

3. A microphone assembly comprising a microphone, a base supporting saidmicrophone, a switch operating lever supported by said base, amulti-contact resilient leaf switch actuated by said switch operatinglever to energize said microphone, a pressure responsive switch on saidbase arranged to energize said microphone when said assembly is raisedfrom a supporting surface and arranged to deenergize said microphonewhen said assembly is resting on said supporting surface, and a switchin series relation with said pressure responsive switch to selectivelyintroduce said pressure responsive switch into the energizing circuit ofsaid microphone.

4. A microphone assembly comprising a microphone, a base supporting saidmicrophone, a switch operating lever supported by said base, amulti-contact resilient leaf switch actuated by said switch operatinglever to energize said microphone, releasable locking means for holdingsaid lever in switch closing relation, a pressure responsive switch onsaid base arranged to energize said microphone when said assembly israised from a supporting surface and arranged to deenergize saidmicrophone when said assembly is resting on said supporting surface, anda switch in series relation with said pressure responsive switch toselectively introduce said pressure responsive switch into theenergizing circuit of said microphone.

5. A microphone assembly comprising a microphone, a base supporting saidmicrophone, a leaf spring switch contained within said base, a switchoperating member arranged to actuate said switch at one side of saidswitch, and a pressure sensitive switch extending from said base andengageable with said leaf spring switch to actuate said switch from theopposite side thereof.

6. A microphone assembly of claim 5 in which said switch operatingmember is biased away from microphone energizing condition by theresiliency of said leaf spring switch.

7. The microphone assembly of claim 5 including a locking means carriedby said base to lock said switch operating member in microphoneenergizing condition.

8. The microphone assembly of claim 5 in which the weight of saidassembly is suflicient to actuate said pressure sensitive switch intomicrophone deenergizing condition when said pressure responsive switchrests on a support.

References Cited in the file of this patent UNITED STATES PATENTS2,183,744 Hubbell Dec. 19, 1939 2,717,932 Rockham et al. Sept. 13, 19552,808,461 Thomas Oct. 1, 1957 ,910,538 Aleksa Oct. 27, 1959 2,918,539Thames et a1 Dec. 22, 1959 FOREIGN PATENTS 156,441 Sweden Oct. 9, 1956

